# Test: Thyristor Mounting

## 10 Questions MCQ Test Power Electronics | Test: Thyristor Mounting

Description
Attempt Test: Thyristor Mounting | 10 questions in 10 minutes | Mock test for Electrical Engineering (EE) preparation | Free important questions MCQ to study Power Electronics for Electrical Engineering (EE) Exam | Download free PDF with solutions
QUESTION: 1

### The usual way to accomplish higher gate current for improved di/dt rating is by using

Solution:

Pilot SCR is an SCR which is fired which activates the firing circuit and fires the main SCR.

QUESTION: 2

### Inter-digitating of gate-cathode regions in SCR devices improves the

Solution:

Inter-digitating is the inter-mixing of the gate-cathode area to improve the di/dt ratings. di/dt rating is improved by providing more cathode conduction area during the delay and rise time.

QUESTION: 3

### The dv/dt rating of SCR can be improved by using

Solution:

Cathode shorts are realized by overlapping metal on cathode n+ layers with a narrow p-region in between.

QUESTION: 4

The total thermal resistance between junction and ambient θjA is 10°C/W. θjc is 2°C/W. θcs is 4°C/W. θsA = ?

Solution:

θjA = θjc+ θcs+ θsA.

QUESTION: 5

Which of the following thermal resistance parameters depends on the size of the device and the clamping pressure?

Solution:

The case-to-sink thermal resistance depends on the size of the device, pressure, grease between the interface, etc.

QUESTION: 6

The sink to ambient thermal resistance of SCR θsA

Solution:

It does not depend on any of the device configurations.

QUESTION: 7

Pav x (θjc + θcs + θsA) =

Solution:

: Pav = (Tj – Ta)/θjA
θjA = (θjc + θcs + θsA).

QUESTION: 8

Heat dissipation from heat sink mainly takes place by

Solution:

Heat DISSIPATION (rejection of heat to the atmosphere) takes place through convention only.

QUESTION: 9

For low power SCRs (about 1 Ampere current) _____________ type of mounting is used

Solution:

Lead mounting is a very simple time of mounting used for low power devices.

QUESTION: 10

In the ___________ type of mounting the SCR is pressed between two heat sinks

Solution:

In the press-pak type the device is pressed or clamped between two heat-sinks & external pressure is applied from both the sides.

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